Electric machines, whether they are motors or generators, are well known in the art. It is also widely known that electric machines generate heat as a by-product and that this heat must be somehow extracted from the machine to improve the performances of the machine and prevent early degradation of the machine.
Conventionally, electric machines are often air-cooled. This is easily done by providing apertures in the body of the machine to let air be forced therein. The efficiency of such a cooling arrangement is poor since air is a generally non-efficient cooling fluid. Furthermore, some electric machines operate in environment that are such that it is not possible to provide an electric machine with apertures.
Electric machines using cooling fluid have also been designed. For example, European Patent Number 0,503,093 entitled “Liquid Cooling Device of Motor” and naming Nakamura as inventor discloses an electric motor where the laminations are provided with apertures allowing an axial flow of cooling liquid when the laminations are assembled. A drawback of Nakamura's system is the risk of failure of the motor caused by leaks. Indeed, a failure-causing link could spring should the seal between adjacent laminations fail.